Obstructive sleep apnea and nocturnal attacks of paroxysmal atrial fibrillation

Study Objectives: Obstructive sleep apnea (OSA) is commonly seen in patients with atrial fibrillation (AF), but it is unclear to what extent this relationship is one of causation or association. We examined a cohort of patients with paroxysmal AF to determine whether the presence of OSA (apnea-hypopnea index >= 15 events/h) affects the time of onset of symptomatic AF episodes. Methods: Patients with a recent emergency department visit for a symptomatic episode of paroxysmal AF were recruited from an AF clinic. The time of onset of the AF attack was classified as occurring in "sleeping hours" or "waking hours" based on direct history from the patient and emergency department visit documentation. Results: Of 152 patients with paroxysmal AF, 67 underwent polysomnography; 1 (1.5%) had central sleep apnea, 46 (68.7%) had mild or no OSA, and 20 (29.8%) had OSA. In the OSA group, 14/20 (70.0%) had their symptomatic AF attack during sleeping hours compared to 12/46 (26.1%) in the mild or no OSA group (P = .001). Compared with those who had a paroxysmal AF attack during waking hours, and adjusting for confounders, those who had a paroxysmal AF attack during sleeping hours had almost 6 times the odds of having OSA (odds ratio, 5.53; P = .007). Conclusions: Compared to patients with paroxysmal AF with mild or no OSA, those with OSA were far more likely to have a symptomatic AF attack during sleeping hours, supporting a causal role for OSA in the pathogenesis of AF in this population. These findings strongly suggest that patients who have nocturnal AF attacks should be evaluated for OSA.